Program trace is one of the important debugging tools that are commonly used by programmers and software engineers. The program trace takes the form of a set of instructions executed by a digital processor. By determining whether certain instructions have been executed, users (for example, programmers or software engineers) can judge whether the hardware and software have properly executed a process. If abnormal operation is determined, a user can then discriminate the source of the problem.
A processor chip such as a microprocessor or microcontroller commonly includes a trace module for the purpose of accommodating firmware development and debugging. In order to monitor information generated by the trace module, a trace data output pin is further required in addition to the standard data input/output pins.
However, the addition of a trace data output pin to a processor chip gives rise to an increase in chip size and cost. Accordingly, it is more burdensome to manufacture a processor chip in this manner.